Browse Prior Art Database

Contact Glide Test

IP.com Disclosure Number: IPCOM000115874D
Original Publication Date: 1995-Jul-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 69K

Publishing Venue

IBM

Related People

Bhatia, CS: AUTHOR [+4]

Abstract

Contact recording, and near contact recording, is accomplished with magnetic read/write heads in contact, or nearly in contact, with the magnetic media. In this context, contact is defined as less than 10 nm physical head to media separation, or fly-height, as might be afforded with air or liquid bearings. To achieve acceptable disk drive life, this implies that the recording media must be free of mechanical disk defects, or asperities, that would significantly degrade the head, or the long term head/disk interface reliability. However, current disk glide height test technologies, even utilizing very low flying glide heads (i.e., <20 nm) do not have the required sensitivity and signal to background to sense asperities that would lead to excessive wear, and destroy contact recording data heads.

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Contact Glide Test

      Contact recording, and near contact recording, is accomplished
with magnetic read/write heads in contact, or nearly in contact, with
the magnetic media.  In this context, contact is defined as less than
10 nm physical head to media separation, or fly-height, as might be
afforded with air or liquid bearings.  To achieve acceptable disk
drive life, this implies that the recording media must be free of
mechanical disk defects, or asperities, that would significantly
degrade the head, or the long term head/disk interface reliability.
However, current disk glide height test technologies, even utilizing
very low flying glide heads (i.e., <20 nm) do not have the required
sensitivity and signal to background to sense asperities that would
lead to excessive wear, and destroy contact recording data heads.

      Disclosed is a piezoelectric instrumented contact glide head
and test method that can be used to mechanically test and burnish
magnetic disks suitable for contact recording.  It is not obvious
that this approach would work, as it is well known that when
"conventional" (meaning here-after glide testing with >10 nm
fly-height) piezoelectric glide heads fly below the "PZT Takeoff
Height" (a measure of disk roughness) on a particular disk, the glide
generates so much signal, that discrete asperities cannot be
distinguished from the background (1).  However, the disclosed
contact glide head channel system does indeed have good signal to
background, as...